Nitrogen cold plasma treatment stabilizes Cu0/Cu+ electrocatalysts to enhance CO2 to C2 conversion

Cu-based materials are ideal catalysts for CO2 electrocatalytic reduction reaction (CO2RR) into multicarbon products. However, such reactions require stringent conditions on local environments of catalyst surfaces, which currently are the global pressing challenges. Here, a stabilized activation of Cu0/Cu+-onAg interface by N2 cold plasma treatment was developed for improving Faradaic efficiency (FE) of CO2RR into C2 products. The resultant Ag@Cu-CuNX exhibits a C2 FE of 72% with a partial current density of -14.9 mA cm-2 at -1.0 V vs. RHE (reversible hydrogen electrode). Combining density functional theory (DFT) and experimental investigations, we unveiled that Cu0/Cu+ species can be controllably tuned by the incorporation of nitrogen to form CuNX on Ag surface, i.e., Ag@Cu-CuNX. This strategy enhances *CO intermediates generation and accelerates C-C coupling both thermodynamically and kinetically. The intermediates O*C*CO, *COOH, and *CO were detected by in-situ attenuated total internal reflection surface enhanced infrared absorption spectroscopy (ATR-SEIRAS). The uncovered CO2RR-into-C2 products were carried out along CO2? *COOH ? *CO ? O*C*CO ? *C2H3O ? *C2H4O ? C2H5OH (or *C2H3O ? *O + C2H4) paths over Ag@Cu-CuNX electrocatalyst. This work provides a new approach to design Cu-based electrocatalysts with high-efficiency, mild condition, and stable CO2RR to C2 products.& COPY; 2023 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.